频谱分析仪测量和噪声Agilent Spectrum Analyzer Measurements and NoiseApplication Note 1303Measuring Noise and Noise-like Digital Communications Signals with a Spectrum AnalyzerTable of Contents3 3 3 3 6 7 8 8 9 10 12 14 14 14 16 16 18 19 19 20 20 20 20 20 21 22 23 23 23 24 25 27 28 Part I: Noise Measurements Introduction Simple noise―Baseband, Real, Gaussian Bandpassed noise―I and Q Measuring the power of noise with an envelope detector Logarithmic processing Measuring the power of noise with a log-envelope scale Equivalent noise bandwidth The noise marker Spectrum analyzers and envelope detectors Cautions when measuring noise with spectrum analyzers Part II: Measurements of Noise-like Signals The noise-like nature of digital signals Channel-power measurements Adjacent-Channel Power (ACP) Carrier power ……